The following description of the background of the invention is provided to aid the reader in the understanding of the invention, but it is not admitted to constitute or describe prior art to the invention.
The collection of biological samples from the field, such as the sampling of water for microbiological contamination testing is an important aspect of maintaining the purity of water supplies.
Samples are often maintained under conditions which will allow for the later growth of any microorganisms present. However, little or no growth of any microorganisms in the sample occurs on site and during shipment of the sample to the testing laboratory. Growth based detection of any microorganism in the sample must await arrival at the testing facility, which delays the detection of the presence of microorganisms. Also, microbiological testing requires incubation of samples at elevated temperatures and such testing is usually done in a laboratory setting.
The use of portable incubation devices for the growth of biological samples, such as cells or tissues in culture is known. Such devices rely on the use of electrical elements such as batteries, heating coils and thermostats to maintain the proper temperature required for cellular growth. See, G. M. Eastham and K. H. Rieckmann, Journal of Tropical Medicine and Hygiene, 84:27-28 (1981) and, Geoffrey A. R. Mealing and Jean-Louis Scwhartz, Brain Research Bulletin, 23:161-162 (1989).
Lemberg et al. U.S. Pat. No. 4,458,674 disclose an infant incubator relying on convection flow from a heating element.